EF6代码第一键不自动递增

我有这样一个类模型:

public class Results
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int Id { get; set; }
    public int GameId { get; set; }
    public Games Game { get; set; }
    public string Notes { get; set; }
    public virtual ICollection<ResultItems> ResultItems { get; set; }
}

由于某些原因，Id字段没有按照模式设置为自动递增:

CREATE TABLE [dbo].[Results] 
(
    [Id]     INT            NOT NULL,
    [GameId] INT            NOT NULL,
    [Notes]  NVARCHAR (MAX) NULL,
    CONSTRAINT [PK_dbo.Results] PRIMARY KEY CLUSTERED ([Id] ASC),
    CONSTRAINT [FK_dbo.Results_dbo.Games_GameId] 
        FOREIGN KEY ([GameId]) REFERENCES [dbo].[Games] ([Id]) ON DELETE CASCADE
);
GO
CREATE NONCLUSTERED INDEX [IX_GameId] ON [dbo].[Results]([GameId] ASC);

我还添加了:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
        modelBuilder.Entity<Results>().HasKey(p => p.Id).Property(p => p.Id).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
        base.OnModelCreating(modelBuilder);
}

到我的数据库上下文中，但是迁移仍然不会使该字段自动增加。有人能看出我哪里做错了吗?

谢谢。

保罗。